Carbon anode



y 1939. J. A. ZITZLER 2,158,996

CARBON ANODE Filed June 5, 1932 INVENTOR Jo/m 19:91am Z [f /er fl W A TORNEY Patented May 23, 1939 PATENT OFFICE CARBON ANODE John Augusta Zitzler, St. Marys, Pa., assignor to Speer Carbon Company, a corporation of Penn sylvania Application June 3, 1932, Serial No. 615,112

7 Claims.

This invention relates to carbon articles to be used as anodes in electron devices such as vacuum tubes.

It is the usual practice to make plates or an- 5 odes of vacuum tubes of some metal such as molybdenum. Molybdenum is not a low cost material and it'has been found that these anodes, particularly in large transmitting types of vacuum tubes, can be very satisfactorily made of, some form of carbon such as electro-graphite, that is, graphite made by electric heatingto a very high temperature and it is an object of the invention to so construct such carbon anodes that they may be readily mounted on the sup- 15 porting wires in the vacuum tube and be held in place without any clamps or binding posts.

Other objects of the invention will appear in the following description, reference being had to the accompanying drawing in which 5.5 Fig. 1 is a side elevation of the carbon anode electro-graphite I and 2 have oppositely facing 35 channels 3 and 4 when in assembled position. Each of these members 3 and 4 is machined from a block of graphite, rectangular in form, and of the correct dimensions. The machining is accomplished by grinding the outer surface of each 40 to produce the wall contour 5 and B and longitudinally-extending flanges 'l and 8. The inside channels 3 and 4 of the members I and 2 are machined by grinding out the carbon to form the inner walls 9 and H], a flattened or oblate 5 cylinder thus being formed when-the parts are placed in juxtaposition. In order to hold these two parts together one of them, for example,

, member I, is machined by grinding out the under-cut or dovetail groove ll transversely 50 through the flanges, as shown, particularly in Figs. 1 and 2. The other member, for example,

2 is likewise ground to form a tongue 12 with diverging sides, as clearly shown in Figs. 1 and 3. To form a support for the wire standards in the 55 vacuum tube that hold the anode or plate in position, longitudinal grooves I3 are machined in the face of the flanges of one member as shown in Fig. 2, and similar grooves M are machined in the face of. the flanges of the other member, as shown in Fig. 3. These grooves are preferably made semi-circular in form by thin grinding wheels so that when placed together they will form a substantially circular hole for reception of the supporting wires or standards.

After the two parts or members are constructed as just described they are fitted together by sliding one parallel to and transversely of the other with the tongue [2 fitting in the groove l I. When they are arranged in the position shown in Fig. 4 they are ready for mounting on wires or 5 standards in a vacuum tube (not shown) and the wires firmly lock the two parts of the anode together because they prevent the transverse sliding movement necessary to separate one member from the other. The grooves l3, l4, 0 should be machined so that they will make a snug fit with the supporting wires and thus hold the anode rigidly in position.

The two members may be ground and grooved somewhat differently, as shown in Fig. 5. Here 5 the dovetail or under-cut groove is machined lengthwise in the flanges so that one under-cut side i5 is in the flange at one side of a member and the other end out side I6 is in the other flange of the same member. The diverging tongue is likewise machined lengthwise of the other member so as to have diverging side strips I1 and I8 interfitting with the under-cut sides l5 and iii. In this case the two members are slid together longitudinally instead of transversely. The grooves are likewise machined longitudinally of the flanges to form the holes l1, l8, for reception of the supporting wires or standards.

The supporting wires fitting in the holes ll and I8 will not lock the two parts together as in the form shown in Figs. 1 to 4 inclusive. Therefore it is preferable to slightly taper the grooves l5, I6, and the tongue members l7, I8, so that they will become tighter as they are slid longitudinally together making a very firm and tight fit when completely assembled. as shown in Fig. 5. Such a taper fit may also be used in the form shown in Fig. 1.

In Fig. 6 I have shown the two members machined substantially as in Fig. 5, with the exception that the holes l1 and I8 are omitted and grooves I9 and 20 machined in the edges of the flanges to receive the supporting wires. The supporting wires may be properly bent when the anode of this modification is applied so as to hold the anode in position.

By constructing the anodes in the way outlined above a very accurate element is produced that gives the required spacing when the parts are assembled in the tube with the filament and grid elements While I have described the invention in connection with electro-graphitic form of carbon, it will be obvious that any other form of carbon or other desired material may be substituted for the graphite.

Having described my invention, what I claim is:

l. A carbon anode adapted to be held by supporting wires consisting of two members having oppositely facing U-shaped channels forming a hollow cylinder, the contacting edges of said members having interfitting tongues and grooves extending transversely thereof whereby the members may be moved transversely of the channel but not longitudinally thereof.

2. A carbon anode adapted to be held by supporting wires consisting of two members having oppositely facing U-shaped channels forming a hollow cylinder, the contacting edges of said members having interfitting tongues and grooves extending transversely thereof whereby the members may be moved transversely of the channel but not longitudinally thereof, and contacting sides having oppositely facing surface grooves extending longitudinally thereof and forming holes for said wires.

3. A carbon anode consisting of two members having oppositely facing U-shaped channels forming a hollow cylinder, the sides of one of said members having under-cut grooves extending transversely thereof and in line with each other across the channel and the sides of the other member having tongues with divergent sides extending transversely thereof and in line with each other across the channel and adapted to make a sung sliding fit with said grooves.

4. A carbon anode consisting of two members having oppositely facing U-shaped channels forming a hollow cylinder and flanges extending outwardly from the sides of the channels, the flanges of one of said members having under-cut grooves extending transversely thereof and in line with each other across the channel and the flanges of the other member having tongues with divergent sides extending transversely thereof and in line with each other across' the channel and adapted to make a snug sliding fit with'said grooves.

5. A carbon anode adapted to be held by supporting wires consisting of two members having oppositely facing U-shaped channels forming a hollow cylinder, the sides of one of said members having under-cut grooves extending transversely thereof and in line with each other across the channel and the sides of the other member having tongues with divergent sides extending transversely thereof and in line across the channel and adapted to make a snug sliding fit with said grooves, said sides having oppositely facing grooves extending longitudinally thereof and forming holes for said wires.

6. A carbon anode consisting of two members having oppositely facing U-shaped channels forming a hollow cylinder, and flanges extending outwardly from the sides of the channels, the flanges of one of said members having undercut grooves extending transversely thereof and in line with each other across the channel and the flanges of the other member having tongues with divergent sides extending transversely thereof and in line with each other across the channel and adapted to make a snug sliding fit with said grooves, and said flanges having holes extending transversely thereof across the said grooves and tongues to receive supporting and locking wires when positioned together.

7. A carbon anode for vacuum tubes consisting of two members having contacting edges and oppositely facing channels therebetween to form an enclosed electron collecting surface and interfitting parts at said edges to prevent movement of the members in at least one direction.

JOHN AUGUSTA ZI'IZLER. 

